Memory protections in Snow Leopard are still too weak, though it shows other improvements

Apple has been bragging about the
security of its new operating system, OS X 10.6 "Snow Leopard".
Leaping from Leopard to Snow Leopard, Apple gives its users limited
antivirus/anti-malware protection (the feature currently only detects
two signatures out of a handful of known OS X malware
signatures).

Still, security experts aren't
so hot on Snow Leopard, criticizing the operating system's
default firewall setting of "off", its lack of fully
automatic updates, and weak anti-phishing efforts for Safari.
They also weren't impressed that Apple shipped with a vulnerable
version of Flash, which downgrade users from the
safer current version.

Now one prominent Mac hacker has
pointed out a significant difference that makes Snow Leopard less
secure than the upcoming Microsoft OS, Windows 7.

Charlie
Miller, of Baltimore-based Independent Security Evaluators, the
co-author of The Mac Hacker's Handbook, and winner of two consecutive
"Pwn2own" hacker contests is about as experienced as OS X
hackers come. He recently criticized
Snow Leopard, stating, "Apple didn't change anything.
It's the exact same ASLR as in Leopard, which means it's not very
good."

ASLR is address space layout randomization, a
security technology that randomly assigns data to memory to make it
tougher for attackers to determine the location of critical operating
system functions. According to Mr. Miller, unlike Windows 7,
which features robust
ASLR, Snow Leopard's ASLR is half-baked. It does not properly
randomize the heap, the stack and the dynamic linker, the part of
Snow Leopard that links multiple shared libraries for an executable.
This means that it's much easier for hackers to attack Snow Leopard
via memory injection than Windows 7.

Still Mr. Miller offered
some praise for Apple. They rewrote QuickTime X, their video
player, largely from scratch fixing many holes and insecurities in
the process -- including an exploit Mr. Miller had been saving.
He states, "Apple rewrote a bunch of QuickTime, which was really
smart, since it's been the source of lots of bugs in the past.
They've shaken out hundreds of bugs in QuickTime over the years, but
it was still really smart of them to rewrite it. [Still] I'd
reduce the number of file formats from 200 or so to 50, and reduce
the attack surface. I don't think anyone would miss them."

He
also praises Apple's relatively effective implementation of DEP (data
execution prevention), another memory protection scheme that Windows
7 also has. DEP is also present in Windows XP Service Pack 2
(SP2) and Windows Vista. Still without ASLR, DEP is only so
good he says. He states, "Snow Leopard's more secure than
Leopard, but it's not as secure as Vista or Windows 7. When
Apple has both [in place], that's when I'll stop complaining about
Apple's security."

So why aren't Macs being exploited
left and right and why can Apple still air commercials claiming
superior security? Mr. Miller states, "It's harder to
write exploits for Windows than the Mac, but all you see are Windows
exploits. That's because if [the hacker] can hit 90% of the machines
out there, that's all he's gonna do. It's not worth him nearly
doubling his work just to get that last 10%."

"Google fired a shot heard 'round the world, and now a second American company has answered the call to defend the rights of the Chinese people." -- Rep. Christopher H. Smith (R-N.J.)